383 Short Block Engine Build - Open-Box Policy

GMPP's 383 Short-Block Serves As The Foundation For A Complete Brodix Top-End Kit

Our bang-for-the-buck mentality can lend to a host of great ideas and combustive mixtures for making super power on short coin. Don't get us wrong--we love a great custom engine combination making freight-train steam that sends the earth's rotation twisting in the other direction. However, we also still have an affinity for proven short-block combination builds. For the street, our theory for boxed engines has yet to be questioned.

It was important to begin our build on solid ground. GM Performance Parts (GMPP) might as well be called Engines "R" Us, because its catalog is basically a toy store for the itchy automotive soul. Our insatiable appetite for GMPP's ready-to-go short-blocks made the company an easy choice for cost-effective power. The offerings range from sedate two-bolt main 290hp 350s and more muscular and complete 383 turnkey engines to the baddest of the bad, such as the 720hp 572ci big-block. Now, we can't help but get our hands dirty, and the 383 carries the best of both worlds for the street. While we appreciate GM's willingness for drop-in-style turnkey motors with all the bells and whistles, we also wanted to take full advantage of Brodix's new top-end kit.

There we opted for the 383 short-block crate engine (PN 12499106) for a solid foundation. This assembly features a four-bolt main with a one-piece rear main seal, the perfect starting point for solid, reliable power in a box. Inside resides a forged 4340 steel 3.800-inch stroker crankshaft, heavy-duty 5.700-inch connecting rods, and hypereutectic dished pistons--needing only a valvetrain and top end to complete the engine.

For just about $1,950, Brodix will pull out complete matching aluminum 200cc intake runner cylinder heads and a dual-plane manifold combo unlike any other. While the heads come standard with 64cc chambers, we had Brodix mill them to 58 cc (additional $212), bumping the compression ratio. We also took advantage of the CNC combustion chambers option, which added $227 to the tab. Even at 58 cc, pump gas is still a reality with this kit, plus Brodix makes sure to supply everything needed to button up the top end.

What's more is our Comp valvetrain took full advantage of the Brodix package. The Comp 'stick we chose came with 242/248 degrees of duration at 0.050 and 0.540/0.562 inch lift on intake/exhaust. We even topped the valvetrain off with Comp's newest member, the Ultra-Pro Magnum roller rockers with a 1.52:1 ratio.

As usual, we followed the build at Westech Performace Group, as Steve Brul put up the wrenching. We threw in the Comp goodies, bolted on the Brodix top end, installed a Holley 750, and strapped the 383 to the dyno to get the numbers all in one day. Our combo was good for 466 hp and 456 lb-ft, and we even ran the mill to 7,000 rpm to showcase its upper-rpm potential. Read on to see how we pulled it off.

Quick NotesWhat We DidPieced together a reliable yet potent 383 combo for the street

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383 Short Block Engine Build - Open-Box Policy

Aside from having to tear open the pallet, our GMPP 383 short-block is essentially ready to drop into an engine bay. Not only does it come with a composite (plastic) timing cover and brass freeze plugs, but it also comes with an 8-inch externally balanced damper. For our testing purposes, we borrowed Westech's TCI Rattler damper.

For pistons, GM uses 9.1:1 hypereutectic aluminum slugs to fill the 4.00-inch bore with a dished top and offset pins.

The GMPP 383 comes bare with no valvetrain. No worries, though; we enlisted a set of 0.842-inch-diameter Comp hydraulic roller lifters (PN 875-16). GMPP also drills and taps for oil pipe plugs, and a fuel block-off plate is also included.

A 4-quart oil pan (5 quarts with filter) comes with the short-block and is loosely bolted to the pan rail with a one-piece rubber gasket.

Yup, this 383 comes with just about everything. The oil pump and windage tray were already installed. For those ready to mate an automatic transmission onto the back, this GM 383 also ships with a 123/4-inch flexplate.

If you still aren't convinced about the quality of this 383 short-block, how does a 3.800-inch forged 4340 steel crankshaft sound with four-bolt mains? Rod journals measure in at 2.10 inches, and the mains are standard 350 journals.

To get the camshaft in place, we removed the surrounding 5/16-inch bolts from the timing cover. Once it was prelubed and installed, Brul locked it in with the cam plate and installed the double-roller timing chain set. It fit beneath the composite GM timing cover without any trouble.

RollersWe couldn't help but try out Comp's latest line of innovative rocker arms. Ultra-Pro Magnums are cast 8650 chromoly bodies and have hardened roller tips. The new weblike design delivers nearly a 29-percent increase in strength and rigidity. They also feature an oversized trunion and precision-sorted needle bearings for use with high-load valvesprings. Even better, they're rebuildable and come with a lifetime guarantee.

The Brodix top-end kit even comes with a Fel-Pro head gasket set (FPP-1003). Brul set them into place and applied thread sealer to each head bolt (supplied with the kit), threaded them down, and torqued them to 65 ft-lb. Note: the gaskets are directional.

Iron KillerThe Brodix 200cc cylinder head package is hard to beat. For just $1,950 you get a complete aluminum head package, including a dual-plane manifold, tall valve covers, intake bolts, and all the necessary gaskets.

Intake valves measure 2.020 inches, and the exhaust valves come in at 1.600 inches. Brodix will clean and blend the bowls, and we even had the company CNC the combustion chambers (machine port, $227.30 extra) and mill the cylinder heads ($212.10 extra) so we could reach a 58cc combustion chamber volume. Also, the intakes were port-matched for increased performance.

The roller lifters were presoaked in oil, and we dropped them into each lifter bore with their coordinating H-bars. Brul spec'd our pushrod length at 7.300 inches (PN 7949-16) and proceeded to fasten down each rocker with a lock-nut.

From there, we laid down a bead of silicone. Then, using the supplied intake gaskets, we planted down the Brodix dual-plane manifold. We were ready to load this 383 onto the dyno. Brul and Eugene Walde added a Holley 750 and an MSD Pro-Billet distributor (PN 85551) with a set of 13/4x31/2-inch Hedman headers.

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